Program Director/Principal Investigator (Last, First, Middle): Khshnan-Sarin, Suchltra/O'Malley, Stephanie S. SPECIFIC AIMS: The purpose of this Laboratory Core is to support research carried out under the auspices of the proposed Center by providing objective and quantitative estimates of exposure to selected tobacco related drugs /compounds, as reflected by their concentrations in biological fluids. Consistent with one of the priorities in the FOA, the proposed projects are concerned with reducing addiction through better understanding of how , some prevalent modifications in the content of tobacco products may influence risk of addiction to nicotine. Research strategies include administration, by various routes, of nicotine alone, and in conjunction with other selected additives, including menthol, that may influence responses to nicotine. Optimal interpretation of study outcomes requires that variations in nicotine and/or menthol exposure across individuals and experimental arms be considered. The initial list of analyte targets includes nicotine, cotinine, trans 3-OH cotinine/cotinine (OHC/C) ratios, menthol glucuronide and unconjugated menthol (for in-vitro solutions). However, the Laboratory Core^will have the ability to set up other assays as mandated by the evolving needs of the center... General Rationale For An On